Method of coating objects



Nov. 29, 1960 E. w. MENKE METHOD OF COATING OBJECTS 5 Sheets-Sheet 1 Filed Oct. 2, 1957 INVENTOR. Edward Z0: 7776 1114? [Igor 6:9.

Nov. 29, 1960 Filed Oct. 2, 1957 E. w. MENKE 2,962,389

METHOD OF COATING OBJECTS 5 Sheets-Sheet 2 NOV. 29, 1960 w, MENKE METHOD OF COATING OBJECTS 5 Sheets-Sheet 3 Filed Oct. 2, 1957 INVENTOR. Edward Z W677 Z 1? Nov. 29, 1960 E. w. ME NKE METHOD OF COATING OBJECTS 5 Sheets-Sheet 4 Filed Oct. 2, 1957 NOV. 29, 1960 w, MENKE 2,962,389

METHOD OF COATING OBJECTS Filed Oct. 2, 1957 5 Sheets-Sheet 5 PREPARING GLASS COPPER FOR PROCESSING 04 /a0 coPPER AND FLUX HEATING GLASS PLACED IN CRUCIBLE TO DESIRED TEMPERATURE a6 a; CRUClBLE AND CONTENTS PLACED IN MELTlNG FURNACE AND COPPER MELTED MELT RETAINED. AT DEsIRED TEMPERATURE PROCESSED GLASS PLACED IN LEHR OR OTHER MEANS TO SLOWLY COOL GLASS AND COPPER BONDED THERETO 6 INVENTOR.

EDWARD W. MENKE //6 AT TOR NFY METHOD OF COATING OBJECTS Edward W. Menke, Hanover Ave., Yorktown Heights, NY.

Filed Oct. 2, 1957, Ser. No. 687,782

11 Claims. (Cl. 117-54) This invention relates to a novel method of coating objects with molten copper or copper alloys and more particularly for spraying such objects with molten cop per or copper alloys and effecting thereby a metal to material bond heretofore unknown in the art.

I-Ieretofore copper has been sprayed in a molten state on objects and materials bythe use of a technique wherein pure or alloyed metal in the form of wire was melted in the flame of a flame gun and atomized by compressed air into a fine spray. This prior art process is known as the Schoop process, and is disclosed in Schoop Patent 1,128,058. In accordance with the Schoop 4 process, although the metal is molten when it leaves the gun, the blast of cool air cools it so that by, the time it impinges on the surface of the material or object to which' copper alloy on the surface of objects such as glass or suitable ceramic. In accordance with-the invention the entire mass of copper or copper alloy which is to. be used as the coating metal is first converted into a.

molten state, preferably before it is poured from a melting crucible into a receiving and holding crucible in a novel spray gun. If desired, however, the entire mass of coating metal, which may be substantially pure copper or a copper alloy, hereinafter sometimes designated as copper coating meta may be converted into the desired molten state in the gun. The important requirement is that the metal be converted to a molten state before it leaves the confines of the gun and remain in that state until it is actually applied. The molten metal in the gun is next conducted by conduit means through a nozzlejet to a point where it is atomized by what 1 term an innocuous compressed gas heated to a high temperature under controlled pressure by the use of a conventional valve, and then is sprayed upon the surface which has been selected for this purpose, such as glass or ceramic. The surface of the material to be coated is prepared by cleaning it, and then is heated to a high temperature, such that when the molten atomized metal impinges upon it, the metal becomes in effect an integral part of the glass (or ceramic). Because of my novel method, surface shock on the materialbeing coated is substantially eliminated or held to a bare minimum and an extremely uniform inseparable layer of metal of desired thickness is formed thereon.

The use of an innocuous gas, which may be an inert,v

or non-oxidizing gas, such as nitrogen, heated above the melting point of copper or a selected copper alloy, in-

sures that there will-be no oXidization of the coating.

metal or coating medium being sprayed and also that it 2,962,389 Patented Nov. 29, 19

ice

molten mass of coating metal in any suitable or desired quantity such that any and all gas in the molten metal mass is occluded. Thus, as a result, only a continuous stream of pure coating metal, i.e., molten copper or copper alloy, can flow in and from the gun and be atomized intoa molten metal spray for discharge onto the selected surface to be coated.

It is an object of the invention to provide a novel process of coating molten copper and copper alloys on.

selected objects, such as glass or ceramics.

- It is also an object of the inventionto providea novel method of spraying substantially pure molten copper or a selected copper alloy on glass or ceramicsheated to a temperature wherein the molten metal spray does not freeze on the surface being coated until an inseparable bond is created and further wherein the molten coating metal'is maintained constantly in that state even though atonized because of the fact that it is atomized by a highly heated, compressed, iner-t or non-oxidizing gas, and means are provided for insuring that the tem perature of the gas will not drop below that of the molten metal when the latter is atomized.

The invention is further characterized by so controlcrucible in the gun to and through the nozzle jet. Even though the gas expands at the point where it atomizes the molten metal, its temperature does not drop appreciably below that of the temperature of the molten selected copper or copper alloy.

Thus the temperature of the atomized molten copper or copper alloy when it strikes the surface to be coated coating metal.

The invention is further characterized by the provision mized, molten state is sprayed upon the surface of the selected object in' order to form a substantially inseparable layer of such metal thereon.

The invention further consists in the provision of a novel method of spraying molten, substantially pure copper or copper alloys on glass or ceramic surfaces wherein the temperature relationship between the'moltenv coating metal being sprayed and the material being coated is such that surface shock is substantially avoided or. eliminated, and exceptionally uniform, inseparable metalto glass or ceramic surface bonds heretofore unknown in the art are obtained.

With these and other objects not specifically mentioned in view, the invention consists in certain combinations and constructions which will be described 'more fully herein.-'

after, and then set forth in the" claims hereuntov appended.

In the accompanyingdrawings which form a part "off this specification and in which like characters of reference indicate the same or like parts;

gun Y g' einven tion,

Figure 1 is a; plan view ,of a preferred: form of spray- Figure 2 is a sectional view taken on line 22 in Figure 1,

Figure 3 is a sectional view taken on line 3-3 in Figure 1,

Figure 4 is an enlarged sectional view of preferred form of nozzle,

Figure 5 is a sectional view taken on line 5-5 in Figure 2,

Figure 6 is a plan view taken on line 6-6 in Figure 2, and

Figure 7 is a diagrammatic illustration or flow sheet showing one way of practicing the method of the invention.

Referring to Figures 1-6 of the drawings, 10 designates generally a conduit which surrounds or encircles the body of the device which is used to apply a selected copper coating metal to the surface to be treated. In this case, the device is a spray gun designated 11. Conduit 10 is provided for carrying a combustible fluid, such as a mixture of gas and air. A valve 20 of suitable conventional design serves to control the quantity of combustible fluid required for the proper operation of gun 11, and to cut ofi the supply thereof when this is desired.

Gun 11 is formed with side walls 12, and end walls 14 and 15. As shown in Figures 1 and 2, end wall 14 is substantially circular for a purpose described more in detail hereafter. Gun 11 also is provided with a bottom 16, preferably removably mounted in any suitable manner on the gun, a fixed top portion 17 and a removable top portion or cap 19. Cap 19 is provided with an opening or flue 22 located above crucible 24 which is seated in the circular end portion 14 of gun 11 and holds the molten, copper coating metal, such as substantially pure copper or a selected copper alloy.

Conduit 10 is provided with a plurality of openings 26. In the form of gun shown there are ten openings, although more or less could be used. Removably mounted in each opening is a vertically extending, elongated airgas manifold 28, each having a plurality of air-gas burners 30. As shown, each manifold 28 has three burners. Each burner 30 has an adjustable valve 32 which can be operated in order to control the quantity of air-gas mixture to be burned. This arrangement makes it possible to control the temperature of the gun 11 and all internal parts thereof within close limits, and thereby insure uniform gun temperature, with substantially complete freedom from hot or cold spots in the gun.

Referring to Figures 2 and 3, it will be seen that detachably mounted gun bottom 16 is formed of a sheet metal shell, such as stainless steel, which I have found withstands the extremely high temperature to which the gun is subjected. Bottom 16 is filled with fire clay and firecrete mixture 36.

Located within gun 11 is a heating coil designated generally 38 by means of which a suitable, highly heated, non-oxidizing or inert gas, such as nitrogen, argon, helium, is conducted to nozzle N and used in atomizing the molten, copper coating metal, such for example as copper or a copper alloy, for appliction to the surface to be coated. One end of coil 38 is connected by a suitable conventional valve 40 to conduit 42 attached to a source of supply (not shown) of compressed gas, such as nitrogen. Coil 38 is formed from a high melting point metal in order that it can withstand the great heat to which it is subjected during the operation of the gun. I have found that a chrome iron alloy, known as Kanthal A-l, serves this purpose satisfactorily. End 37 of coil 38 is secured in position by a clamp 44 attached by screws 46 to conduit 10. As illustrated in Figures 1 and 2, the top of heating coil 38 is provided with an elbow 48 to which is attached a length of pipe 50 formed from the same material as coil 38.

The free end of pipe 50' is threadably secured in elbow 52. Also threadably joined to elbow 52 is one end of a nipple 54, the other end of which is threadably secured in 4 nozzle body 56. A suitable filter 58 which may be formed of Kanthal A-l or Nichrome wire, about .002 inch in diameter, is mounted in nipple 54 adjacent the point where it is attached to nozzle body 56. Nozzle body 56 is provided with an axial bore 57 and a transverse bore 59 greater in diameter than axial bore 57 in which the end of nipple 54 is secured, as described hereinabove.

Nozzle body 56 is provided with a section 60 having screw threads 62 adapted to accommodate the internally threaded portion of the crucible holder 64. This connection permits ready and easy removable mounting of crucible holder 64 on nozzle body 56 because threads 62 are fairly coarse. Mounted in the threaded portion of crucible holder 64 is a soft graphite rod 66 in which is formed an axial bore 68. A plurality of radially extending holes or openings 70 are drilled or otherwise formed in rod 66, as shown in Figures 2 and 4. These holes or openings filter the molten coating metal M as it flows from crucible 24 into bore 68 in graphite rod 66.

The end portion 14 of gun 11 is substantially circular in shape in order to best accommodate crucible 24 which is circular in cross-section. It is evident, however, that a different shape could be given to gun portion 14 if desired. Crucible holder 64, preferably made of Kanthal A-l, supports crucible 24 which is made of Denver clay or equivalent material. As in the case of bottom 16 of gun 11, walls 12 and end portions 14 and 15 are made in the form of metal shells, preferably from stainless steel, filled with a mixture of fire clay and firecrete. Crucible 24 is held seated in crucible holder 64 by a mixture of fire clay and firecrete 65.

Sealed in an axial bore 57 in nozzle body 56 is a nozzle jet 72. As shown in Figures 2 and 4, nozzle jet 72 is a small tube formed from hard graphite through which the molten copper coating metal or alloy flows from crucible 24 through openings 70 into and through bore 68 and thence through nozzle jet 72 and out of the lower end thereof, as viewed in Figures 2 and 4. As the molten stream of coating metal leaves the end of nozzle jet 72, it is atomized by the heated nitrogen gas under pressure flowing through nipple 54 and out of orifice 80. As mentioned hereinabove, the nitrogen gas is heated to a temperature greter than, or at least as great as, that of the molten metal it atomizes so that even though there may be a drop in gas temperature due to expansion, there is substantially no drop in temperature in the molten metal as it flows out of nozzle jet 72 as the result of its contact with the highly heated gas. This maintenance of temperature of the atomized, molten metal or alloy is of marked importance in achieving the novel results of my invention because it insures that molten metal actually is applied to the surface being coated.

Bore 57 passes through transverse bore 74 in nozzle body 56. Bore 74 is partially filled with a suitable, high temperature cement 76 by means of which nozzle jet 72 is held rigidly in operating position in nozzle body 56. The right hand end of bore 59, as viewed in Figure 4, is closed by the threaded end of rod 78 suitably mounted on conduit 10. The lower end of nozzle jet 72 extends through a circular opening or orifice 80 formed in nozzle body or holder 56. Orifice 80 connects directly with bore 59. Hence, as the stream of heated pressurized nitrogen gas flows through nipple 54 and passes through orifice 80, it comes in contact with molten, copper coating metal flowing by gravity through and out of nozzle jet 72. The aspirating effect of the nozzle construction and the compressed gas causes a differential in pressure thus helping gravity in the free flow of molten metal from nozzle 72. At the point of contact of the pressurized gas and molten metal stream, the molten metal will be atomized thereby and because of the temperature characteristics of the heated, pressurized gas and the molten metal at this point, the molten metal, though now in an atomized state, remains molten and is sprayed in this state upon the surface of the work to be treated. The

assayed;

work being coated, as indicated somewhat diagrammatically in Figure 2, may be a heated, glass object G or other object which is supported on a suitable, heated support designated generally H and heated in any suitable manner as by an electric heater E.

There are thirty openings 82 formed in the side walls 12, and end walls 14 and 15 of gun 1-1. This number, together with openings 83, provided for auxiliary burners 31 in the lower section of wall 14, has been found to give satisfactory results although more or less could be used if desired. Burners 30 and 31 direct their flames into the gun in order to heat coil 38 and maintain the coating metal in crucible 24 in a molten state. In the case where frozen metal is placed in crucible 24, the heat generated by burners 30 and 31 is suflicient to convert it to a molten state and maintain it in that condition.

Conduit is removably attached to gun 11 by means of a plurality of brackets 86 and screws 88. Gun 11 has several openings 89 through which thermocouples (not shown) of suitable, conventional design may be inserted for cooperation with suitable means (not shown) for controlling the temperature within gun 11.

Gun 11 is provided with a detachably mounted bottom cover plate 90 which is located beneath crucible 24, as shown in Figures 1, 2, 4, 5 and 6. Plate 90is attached to gun 11 by screws 91 and is formed with a central, circular opening 92 through which the lower extension part of nozzle body 56 projects. Referring to Figure 2, it will be seen that cover plate 90 covers the bottom of gun 11 below crucible 24 and is sealed on the bottom of gun 11 by a suitable, refractory cement 93. This sealing of plate 90 resultsin more heat in the gun because it prevents cold air from rising against nozzle jet 72 and chilling it, as well as nozzle body 56, crucible 24 and the molten coating metal in crucible 24. Nozzle jet 72 preferably is formed from an extremely hard, compressed, heat treated mixture of graphite and china clay.

Plate 90 prevents the burned gases and free oxygen from,

oxidizing the atomized, copper coating metal being sprayed. Experience has shown that if a small quantity of burned and unburned gas from burners 30 and 31 is allowed to escape from the opening between plate 90 and nozzle body 56, this gas will oxidize the coating metal being sprayed. This condition is avoided by the construction described.

Figure 7 illustrates diagrammatically a preferred method of practicing the invention. Assuming that the material to be coated is a glass surface, it is first cleaned, as by washing. This step is indicated at 100. The glass object is then placed in a suitable heating device or oven, such as 103, as shown in Figure 2, and heated to a suitable temperature, preferably above 1000 F. depending upon the type of glass used, as at 102, and the temperature is held at that range until and while the surface of the heated glass object is being coated with the molten,

atomized metal. Because of this heating step, the molten metal spray will not freeze until an inseparable copper to glass bond is created. Conversely, glass which has just been made can be allowed to cool to the desired temperature and then coated, as above described.

Ceramics to be coated are treated similarly. It is found that a satisfactory range of temperature to which the ceramic being treated is raised is between 1000 F. and substantially the temperaure of the molten copper coating metal, depending upon the softening point of the ceramic to be coated. In some instances, however, it may be desired to heat the ceramic to be coated to substantially the temperature of the molten copper coating metal. Actually, ceramics require a higher temperature than glass for softening and this will vary with the type of ceramic. Thus,- ceramics can be heated much higher than glass which allows a lower temperature for the molten copper in order to bond it inseparably to the ceramic to which it is applied. v I

Examples of glass that have been coated satisfactorily with copper and copper alloys in accordance with my invention are: all types of flat or sheet glass, including" plate glass, bottle glass, drinking glasses, Pyrex and other heat resisting glasses, glass rods, and glass tubing.

Ceramic coated successfully included wall and floor tiles.

107 where the temperature of the molten metal may be raised as high as 2500" F. Preferably, the molten copper is held at a temperature range of about 2000-2300 F. as at 108 until it is transferred to gun 11. During the transfer of the molten copper from the melting fur-.

nace crucible into crucible 24 there may be a slight drop in temperature. into crucible 24, the temperature of the molten copper is. again raised to a temperature range of 2150-2250 F.; or possibly higher.

As noted hereinabove, the particular copper coating metal, selected for spraying, may be converted into a molten state in crucible 24 of gun 11 from which, in the operation of the gun, it flows in a molten stream by gravity and the aspirating effect of the nozzle through nozzle jet 72 for atomization by the pressurized gas flowing through nipple 54. The temperature of the coating metal in this case is conditioned as described above. In either of the two cases where the melt is produced in a melting furnace crucible or in the crucible 24 of gun 11, a flux is placed in the crucible along with the metal to be converted to a molten state. Fluxes which have given satisfactory results are A.B.C. Foundrate 12, a mixture of cuprous oxide, a' relatively low melting point, glassy material and phosphorous copper, and boron sub-oxide.

The preferred method illustrated in Figure 7 includes the optional step of adding a degasifier at 110 to the melt before it is transferred at 112 into crucible 24 of gun 11. This step may be omitted because the flux added at 106 acts' to remove impurities and gas. However, I prefer to use a degasifier because I have found that it contributes to the best possible flow of molten copper through nozzle jet 72, thereby producing a uniform, continuous stre'am'of substantially pure molten copper coating metal for atomization in a markedly uniform, continuous spray. In the case where the coating metal is melted in crucible 24 in gun 11, a degasifier is added before the active spray-ing operation begins.

The use of a degasifier insures that at no time during the coating operation will there be included gases in the copper or copper alloy, i.e., copper coating metal which may be used as the coating medium, which would result in the formation of interrupted and discontinuous atomization of the metal and a non-uniform coating in the final product. I have found that phosphor copper gives satisfactory results as a degasifier. Other well-known types of degasifiers could be used.

Gun 11 is heated to a temperature at least that of the molten copper or copper alloy selected to be sprayed upon the surface to be treated. This temperature will depend upon the copper coating metal being used and the material being coated. Satisfactory temperature ranges for typical copper coating metals are given as follows:

The 't em perature of the glass is relative. Glass stand a temperature of 1000 F. or more before soften- However, subsequent to its being poured ing, and I have found that it is undesirable to heat glass above its'softening point. The softening point of glass depends upon their compositions, as shown in the follow ing table:

In all coating metals referred to above, the desired temperature range satisfactory for spraying is effected by burners 30 and 31 of gun 11, as described hereinabove. While in the embodiment of the invention illustrated herein, a combustible, gaseous fluid is disclosed as the medium for heating and maintaining gun 11 at a high temperature, other heating means, such as electric resistance or induction heating systems, also could be used to advantage.

Gun 11 is held at the temperature specified above until it is ready for use, and also at all other times when the spraying operations are in progress. The temperature of gun 11 is controlled by valves 20 and 40 which are provided for adjusting the quantity of gas-air fed to burners 30 and 31. Thus, after the burners 30 and 31 have been lighted, valves 20 and 40 are adjusted until the desired gun temperature control is effected.

The crucible in the crucible furnace which contains the molten copper at the specified temperature is removed from the melting furnace and a portion of the melt is transferred to crucible 24 in gun 11 as designated at 112 in Figure 7. As shown in Figure 2, glass G, to receive the metal coating, is supported on a suitable electric grid E in an enclosure 103. Glass G preferably is located some four to six inches beneath the bottom of nozzle N. Enclosure 103, shown diagrammatically in Figure 2, is provided with an opening 0, and a door or cover (not shown), which can be opened when the glass G is being coated, and closed at the end of these operations in order that the glass G may cool slowly and equalize the strains and stresses which may have been set up in glass G because of its subjection to heat in being prepared to receive the metal coating, and also because of the heat incident to the actual coating treatment itself. The coated glass may be removed from enclosure 103 and placed in a leer 116 after being sprayed with the molten, atomized copper as at 114, as indicated in Figure 7.

Non-oxidizing or inert gas, such as nitrogen or helium, under pressure, is fed into heating coil 38 and thence through pipe 50 and nipple 54 into bore 59 of nozzle body 56 at a temperature approximately that of the molten metal in crucible 24, or between 2,1502,250 F., or higher. I have found that satisfactory gas pressures may range from 30 p.s.i. up to 80 p.s.i. and even higher. Because of the substantially equal temperature of the molten metal and the atomizing gas upon contact with the molten metal fed through nozzle jet 72, the gas will not cause a sub-standard cooling of the molten metal despite a small temperature drop of the gas due to its expansion at nozzle N. The association of the molten metal and the highly heated, inert gas under pressure results in the formation of a fine molten metal spray which impinges upon the surface of the heated glass in enclosure 103 where it adheres and forms a joinder with the glass in a bond which is permanent and stronger than the glass upon which the metal is coated. As stated hereinabove, the coated glass G, after a stated period of controlled cooling, is removed from a leer or other treating chamber as at 118 in Figure 7.

It will be understood that the reference in the description of the several steps of the preferred method illustrated in, Figure 7 does not obtain solely for coating a selected copper coating metal on glass. The same method can be used equally well in the treatment of ceramics.

The novel spray gun, and the method described hereinabove make possible a simple and efiiective way of forming copper and copper alloy coatings on glass and ceramics which are uniform and extremely durable, and permanent to such an extent that it is practically impossible to remove coatings produced in accordance with the invention from the substances to which they have been applied without a resort to chemical action.

What is claimed is:

1. The method of forming a permanent coating of a copper coating material on a selected object which comprises cleaning the surface of the object to be coated and heating said object to a high temperature approaching but lower than its softening point, converting the coating material to a molten state, degasifying said molten coating material, and while holding said degasified coating material in said molten state allowing it to flow in a continuous stream through a nozzle, atomizing said stream of molten coating material as it moves from said nozzle and projecting it in molten atomized form on said heated surface to be coated.

2. The method of forming a permanent coating of a copper coating material on a selected object which comprises cleaning the surface of the object to be coated and heating said object to a high temperature approaching but lower than its softening point, converting the coating material to a molten state, degasifying said molten coating material, removing substantially all impurities from said molten coating material, and while holding said substantially pure degasified coating material in said molten state allowing it to flow in a continuous stream through a nozzle, atomizing said stream of substantially pure molten coating material as it moves from said nozzle and projecting it in molten atomized form on said heated surface to be coated.

3. The method defined in claim 1 wherein said coating material is substantially pure copper.

4. The method defined in claim 1 wherein said coating material is a copper alloy.

5. The method of forming substantially inseparable permanent layer coatings of copper and copper alloys on objects to be coated comprising preparing the surface of an object to be coated by cleaning said surface, heating said object to a high temperature but below its softening point, converting the selected coating metal to a molten state, degasifying said molten metal, and maintaining said molten degasified metal substantially free from ab sorption of oxidizing gaseous fluids, flowing said degasified molten metal in a continuous and uninterrupted molten stream of substantially pure coating metal through an orifice to a point of atomization, and atomizing said stream of substantially pure molten coating metal and projecting it in a uniform atomized molten spray onto the prepared surface of said object to form thereon said substantially uniform inseparable layer of metal.

6. The method of forming thin uniform inseparable layers of a metal selected from the group consisting of substantially pure copper and copper alloys on the surface of an object, comprising converting said metal into a molten state, filtering said molten metal to remove impurities therefrom. and, degasifying said molten metal, maintaining it in a substantially pure molten condition, and while said metal is so maintained in said substantially pure molten condition, atomizing a stream of said substantially pure molten metal by subjecting it to the in fluence of a highly heated innocuous gas under pressure, whereby said substantially pure atomized metal is applied as a molten spray on the surface of said'objeet.

7. The method of forming a permanent, substantially uniform inseparable metallic layer upon the surface of an article to be coated comprising selecting a coating metal from the group consisting of substantially pure copper and copper alloys, converting said selected coating metal to molten state, degasifying said molten coating metal and removing substantially all impurities, delivering a continuous stream of said molten degasified and substantially pure coating metal to a zone of atomization without substantial drop in temperature, atomizing said stream of molten coating metal into a molten coating metal spray, and applying said molten coating metal spray to the surface of said article.

8. The method of forming substantially uniform inseparable layers of copper on the surface of a glass object comprising cleaning said surface, heating said glass to a temperature ranging between 1000 F. and its softening point and maintaining said temperature within that range, converting said copper into a molten state in a temperature ranging to about 2500 F., and holding said molten copper at a temperature range of about 20002300 F., degasifying said copper to remove impurities, filtering and flowing a continuous stream of said degasified and filtered molten copper through an orifice into a zone of atomization, atomizing said stream of molten copper issuing from said orifice without lowering said temperature appreciably to form a molten copper spray and then applying said molten copper spray to the surface of said heated glass object.

9. The method defined in claim 8 including the step of preventing access of oxidizing gases and free oxygen into said zone of atomization during the formation of said atomized molten copper spray.

10. The method of forming thin uniform inseparable layers of a metal selected from the group consisting of substantially pure copper and copper alloys on the surface of an object selected from the group containing glass and ceramic, comprising converting said metal into a molten state, degasifying and filtering said molten metal to remove substantially all impurities therefrom, said molten metal and maintaining said substantially pure metal in molten condition, and while said substantially pure metal is so maintained in said molten condition, atomizing a 10 stream of said molten metal by subjecting it to the influence of a highly heated innocuous gas under pressure, whereby said substantially pure atomized metal is applied as a molten spray on the surface of said object.

11. The method of forming substantially uniform inseparable layers of copper on the surface of a ceramic object comprising cleaning said surface, heating said ceramic to a temperature ranging between 1000 F. and its softening point and maintaining said temperature within that range, converting said copper into a molten state in a temperature ranging to about 2500 F., and holding said molten copper at a temperature range of about 20002300 F., treating said molten copper to remove substantially all impurities, including degasifying said molten copper, said copper, flowing a continuous stream of said treated molten copper through an orifice into a zone of atomization, preventing access of oxidizing gases and free oxygen into said zone of atomization and, atomizing said stream of molten copper issuing from said orifice without lowering said temperature appreciably to form a molten copper spray and then applying said molten copper spray to the surface of said heated ceramic object.

References Cited in the file of this patent UNITED STATES PATENTS 1,128,058 Schoop Feb. 9, 1915 1,164,008 Moore Dec. 14, 1915 1,663,944 Hopfelt Mar. 27, 1928 1,880,065 Arpin Sept. 27, 1932 2,048,912 Ziska et al July 28, 1936 2,197,274 Menke Apr. 16, 1940 2,322,787 Brennan June 29, 1943 2,639,490 Brennan May 26, 1953 OTHER REFERENCES Newton et al.: Metallurgy of Copper, 1942, John Wiley & Sons, Inc., page 224. (Copy in Div. 3.)

I 'UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No 2' 962 389 November 29 1960 Edward 'We- Menke It is hereby certified that error appears in the above numbered pateht requiring correction and that the said Letters Patent should read as corrected below.

Column 9 lines 35 and 36, strike out "said molten metal and"e Signed and sealed this 23rd day of May 1961;

SEA L) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents 

1. THE METHOD OF FORMING A PERMANENT COATING OF A COPPER COATING MATERIAL ON A SELECTED OBJECT WHICH COMPRISES CLEANING THE SURFACE OF THE OBJECT TO BE COATED AND HEATING SAID OBJECT TO A HIGH TEMPERATURE APPROACHING BUT LOWER THAN ITS SOFTENING POINT, CONVERTING THE COATING MATERIAL TO A MOLTEN STATE, DEGASIFYING SAID MOLTEN COATING MATERIAL, AND WHILE HOLDING SAID DEGASIFIED COATING MATERIAL IN SAID MOLTEN STATE ALLOWING IT TO FLOW IN A CONTINUOUS STREAM THROUGH A NOZZLE, ATOMIZING SAID STREAM OF MOLTEN COATING MATERIAL AS IT MOVES FROM SAID NOZZLE AND PROJECTING IT IN MOLTEN ATOMIZED FORM ON SAID HEATED SURFACE TO BE COATED. 